Internal-combustion cylinder head assemblies

ABSTRACT

An internal-combustion engine cylinder head assembly comprises an induction passage having two portions in the form of surfaces of revolution generated about different axes. The axis of the downstream portion is coincident with the axis of the inlet valve, and the plane of symmetry of the passage contains the axis of the valve and the axis of the engine cylinder.

United States Patent Grosseau {45} Apr. 9, 1974 [5 1 INTERNAL-COMBUSTIONCYLINDER 2,865,354 12/1958 Frank 123/188 0c HEAD ASSEMBLES 3.422.8051/1969 Dzianott 1. 123/188 M [75] Inventor: Aibert Grosseau, Chaviile.France FOREIGN PATENTS OR APPLICATIONS 73 Assigneel Societe AnonymeAuwmobiles 1.015.555 1/1966 Great Britainnflumnnnn 123/188 M Citroen,Paris. France Primary Examiner-Laurence M. Goodridge [22] Ffled' 1971Attorney, Agent, or Firm-Arnold Robinson; William [21] Appli No: 213,011D. Lucas; Frank J. DeRosa [52] US. C1. 123/193 H [57} ABSTRAC! [51 1Int. Cl. F02f 1/00 {58} Field 0 searchmn 2388 M, 188 GC 188 S, Anmternal-combnstton engine cylinder head assembiy comprises an inductionpassage having two per- 123/1881, i93H hens in the form of surfaces ofrevolution generated 56 I References Cited about different axes. Theaxis of the downstream portion is coincident with the axis of the inletvaIve. and UMTED STATES PA TENTS the plane of symmetry of the passagecontains the axis 3.429.303 2/1969 Roberts 123/193 H 0f the valve andthe axis of the engine cylinder, 1,088.25) 2/1914 Brown 123/188 GC3,444,852 5/1969 Henry-Biaband .i 123/188 M 10 Claims, 4 Drawing FiguresPATENTEDAPR 9 i974 SHEET 2 [IF 4 INTERNAL-COMBUSTION CYLINDER HEADASSEMBLIES BACKGROUND OF THE INVENTION 1. Field of the Invention Thepresent invention relates to cylinder head assemblies forinternal-combustion engines.

2. Description of the Prior Art To obtain from an internal-combustionengine a high specific power, equal to at least 80 HP. S.A.E., forexample, it is necessary that the cylinders be satisfactorily chargedwith fuel-air mixture. The conditions to be fulfilled for this purposeare easier to provide in the portion of the induction system which liesoutside the cylinder head than for the portion within the cylinder headsince the shape and surface finish of induction passages externally ofthe cylinder head can be provided as desired.

Induction passages within the cylinder head should create only verysmall pressure drops, as can be ensured by uniformly shaping the passagecross-section, and by providing steady and smooth progressions fromsection to section and a good surface finish on the passage walls.

In any given engine, the dimensions and surface finish of the inductionpassages feeding each of the cylinders should vary within the narrowestpossible limits, being to all intents and purposes identical for allcylinders, failing which there may be a serious lack of bal' ance, suchas to prevent proper running and to shorten the life of the engine. Thisidentity of dimensions and surface finish must also be preserved fromengine to engine, to avoid variation in the maximum output power ofidentical engines.

The cylinder heads of high-power engines can be made of aluminum alloy.In mass production, pressure casting enables correct shaping and surfacefinish to be obtained. The mould stripping conditions, however, preventthe desired shapes from being achieved without resort to expedients suchas, a joint-plane extending into the induction passage or a separatelyfitted passage.

It has been found experimentally that optimum specific power is obtainedfrom an induction passage that is of circular section throughout, thecross-sectional area increasing steadily in the direction of flow. Suchpassages can be produced by final dressing, as practised in the case ofracing engines. Protracted, highly delicate work wiil yield a propersurface finish, but it will not ensure uniformity between the shaping ofone passage and the next.

The use of pressure casting, with a joint-plane within the passage, notonly necessitates additional parts, but adversely affects the maximumpower output because of the irregularities introduced by the joint.

An object of the present invention is to provide a cylinder headassembly having at least one induction passage in which the flowcross-section steadily increases in area from the point of admission tothe cylinder head to the valve seat, but which can nevertheless readilybe machined in mass production.

SUMMARY OF THE INVENTION According to the present invention, there isprovided in an internal-combustion engine cylinder head assembly meansdefining at least one induction passage for feeding fuel-air mixture toan engine cylinder, and an inlet valve controlling flow through theinduction passage, said induction passage being symmetrical about aplane containing the axis of the cylinder and the axis of the inletvalve, and having a first or upstream portion in the form of a surfaceof revolution generated about a first axis, and a second portiondownstream from the first portion and in the form of a surface ofrevolution generated about a second axis coincident with the axis of theinlet valve.

The two portions of the passage can be interconnected by a portion of asphere to which they are tangential. They may be frusto conical at leastfor part of their length.

in one preferred embodiment of the invention, the cylinder head containsthree successive portions in the form of surfaces of revolutiongenerated about different axes. The first or upstream portion in thedirection of flow and the intermediate portion preferably beinginterconnected by a portion of a sphere to which they are tangential.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will nowbe described, by way of example only, with reference to the accompanyingdiagrammatic drawings, in which:

FIG. 1 is a fragmentary cross-section of one embodiment of a cylinderhead assembly in accordance with the invention, the section being takenon a plane containing the axis of an inlet valve and cylinder of theassociated engine;

FIG. 2 is an elevation showing the shape of an induction passage, of thecylinder head;

FIG. 3 is a fragmentary cross-section similar to FIG. 1, of anotherembodiment of a cylinder head assembly; and

FIG. 4 is a section taken on line A-A of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. I a cylinderhead assembly 1 to be positioned at one end of a cylinder having an axisOX, has a machined induction passage 2, and an exhaust passage 3. Theinduction passage 2 ends in a venturishaped seat 4, for an inlet valve5, the stem 6 of which moves in the direction of its longitudinal axisOY.

The induction passage 2 is symmetrical about a plane containing the axesOX and CY. The induction passage 2 comprises, taken in the direction ofHow of the fuelair mixture, a cylindrical portion 20 having an axis 22,joined by a toroidal surface 2b, to a frusto-conical portion 2c,co-axial with the cylindrical portion 2a; the frusto-conical portion 2clies within the acute angle formed between the axis CY and a lineextending at right angles to the axis OK. The portion 20 is tangentialto a portion 212 which forms part of a sphere I having its centre at 8,the point of intersection of the axes CY and 22.. The diameter of thissphere is slightly smaller than D, the diameter of the upstream edge ofthe seat 4. The spherical portion M is joined to the seat 4 by afrusto-conical portion 2e having a base diameter D. The portion 2e isfollowed by a short cylindrical portion 2f, the axes of the portions 2eand 2f being coincident with the axis 0! and being interconnected by atoroidal portion 23. As can be seen from FIG. 2, the frustoconicalportion 2c meets the frusto-conical portion 2: along a curve 9.

It can also be seen, from FIGS. 1 and 2, that a point on the curve 9situated in the plane of symmetry of the passage 2 (the plane of FIG. 1)also lies on the cylindrical portion 2f.

Calculation of the various cross-sectional areas of the passage 2 showsthat the cross-sectional area increases substantially uniformly in thedirection flow, reaching a maximum at the connection to the seat 4; itis thus possible to obtain high values of specific power. Moreover, thepassage 2 can readily be machined for mass production purposes in twostages, namely by boring along the axis 22 using an expanding tool, theadvance of which is programmed according to the profile desired, and bymilling along the axis OY with a ballended profile cutter.

The induction passage 2 in the cylinder head assembly shown in FIGS. 3and 4 is likewise symmetrical about a plane containing the axes OX andCY. it comprises, taken in the direction flow, a cylindrical portion Zahaving an axis Z,-Z,, connected by a toroidal surface 2'b to afrusto-conical portion, tangential c co-axial with the cylindricalportion 2'a. The portion 2'0 is tangnetial to a portion 2'd, which formspart of a sphere 7 having its centre at 8.

The spherical portion 2'd is joined to a portion Z'e, having an axis 2-2,, the latter lying between the axes Z,Z and OY and passing throughthe centre 8. As shown, the portion Z'e is cylindrical (but canalternatively be frusto-conical) and meets the portion 2'c which itintersects along the curve 9'.

The portion 2'e is joined to the seat 4 by a frustoconical portion 2fwhich is followed by another cylindrical portion 2'g, the axis of theselast two portions being co-incident with the axis OY. The portions 2'sand Z'fintersect along a curve 10.

The present invention is not limited to the embodiments described andillustrated. For example, the surfaces of revolution which form theinduction passage 2 could have different longitudinal mid-planes,provided that the axis of revolution of the downstream portion orportions coincide with the axis OY.

What is claimed is:

I. An internal combustion engine intake passage for a cylindercomprising:

a. an upstream portion;

b. an intermediate portion connected to said upstream portion and inopen communication therewith;

c. a downstream portion connected at the downstream end of saidintermediate portion and in open communication therewith;

d. a valve seat positioned at the downstream end of said downstreamportion;

e. a valve adapted to contact said seat to close and open said passage,said valve being positioned with its longitudinal axis intersecting theaxis of the cylinder at an angle;

f. the cross-sectional area of said passage substantially increasing inthe direction of flow from said upstream portion to said valve seat;

g. said upstream portion being defined by a first surface of revolutiongenerated about a first linear axis longitudinally disposed within andextending the entire length of said upstream portion and intersectingsaid longitudinal valve axis at an angle;

h. said intermediate portion being defined by a second surface ofrevolution generated about a second linear axis longitudinally disposedwithin and extending the entire length of said intermediate portion andintersecting said first axis and said longitudinal valve axis atdifferent angles;

i. said downstream portion being defined by a third surface ofrevolution generated about a third linear axis longitudinally disposedwithin and extending the entire length of said downstream portion andcoincident with said longitudinal axis of said valve; and

j. said upstream, intermediate and downstream portions being symmetricalabout a plane containing said cylinder axis and said longitudinal valveaxis.

2. An assembly as claimed in claim I, in which said valve seat is ofventuri shape.

3. An assembly as claimed in claim 1 in which said upstream portion ofthe passage is frusto-conical at least for part of its length.

4. An assembly as claimed in claim 3, in which said upstream portioncomprises a cylindrical portion connected to said frusto-conicalportion.

5. An assembly as claimed in claim 4, in which said upstream portioncomprises a toroidal portion connecting said cylindrical portion to saidfrusto-conical portion.

6. An assembly as claimed in claim 1 in which said downstream portion ofthe passage is frusto-conical, at least for part of its length.

7. An assembly as claimed in claim 6 wherein said downstream portionfurther comprises a cylindrical portion connecting said frusto-conicalportion to said valve seat.

8. An assembly as claimed in claim 1 in which said longitudinal axis ofsaid valve is inclined in relation to said axis of said cylinder andsaid first axis is situated in the acute angle formed between saidlongitudinal axis of said valve and an imaginary line extending at rightangles to said axis of said cylinder.

9. An assembly as claimed in claim 1 wherein said downstream portion ofsaid passage comprises a frustoconical portion and a cylindricalportion, said frustoconical portion of said downstream portion being connected to said intermediate portion of said passage and said cylindricalportion connecting said frusto-conical portion to said valve seat, saidintermediate portion and said cylindrical portion and saidfrusto-conical portion of said downstream portion intersecting saidplane containing said axis of said cylinder and said longitudinal axisof said valve at a point lying on said plane.

10. An assembly as claimed in claim I in which said passage furthercomprises a partially spherical portion disposed between and connectingsaid upstream and intermediate portions, said upstream and intermediateportions being tangential to said partially spherical portion.

a s w a UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION April 91974 Patent No. 3 802 404 Dated Inventor(s) Albert Grosseau It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

In Column 1 before [52] insert "Foreign Application Priority DataDecember 30, 1970 France .47682/70 December 8, 1971 rance ,44763/71"Signed and sealed this 1st day of October 1974,

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents

1. An internal combustion engine intake passage for a cylindercomprising: a. an upstream portion; b. an intermediate portion connectedto said upstream portion and in open communication therewith; c. adownstream portion connected at the downstream end of said intermediateportion and in open communication therewith; d. a valve seat positionedat the downstream end of said downstream portion; e. a valve adapted tocontact said seat to close and open said passage, said valve beingpositioned with its longitudinal axis intersecting the axis of thecylinder at an angle; f. the cross-sectional area of said passagesubstantially increasing in the direction of flow from said upstreamportion to said valve seat; g. said upstream portion being defined by afirst surface of revolution generated about a first linear axislongitudinally disposed within and extending the entire length of saidupstream portion and intersecting said longitudinal valve axis at anangle; h. said intermediate portion being defined by a second surface ofrevolution generated about a second linear axis longitudinally disposedwithin and extending the entire length of said intermediate portion andintersecting said first axis and said longitudinal valve axis atdifferent angles; i. said downstream portion being defined by a thirdsurface of revolution generated about a third linear axis longitudinallydisposed within and extending the entire length of said downstreamportion and coincident with said longitudinal axis of said valve; and j.said upstream, intermediate and downstream portions being symmetricalabout a plane containing said cylinder axis and said longitudinal valveaxis.
 2. An assembly as claimed in claim 1, in which said valve seat isof venturi shape.
 3. An assembly as claimed in claim 1 in which saidupstream portion of the passage is frusto-conical at least for part ofits length.
 4. An assembly as claimed in claim 3, in which said upstreamportion comprises a cylindrical portion connected to said frusto-conicalportion.
 5. An assembly as claimed in claim 4, in which said upstreamportion comprises a toroidal portion connecting said cylindrical portionto said frusto-conical portion.
 6. An assembly as claimed in claim 1 inwhich said downstream portion of the passage is frusto-conical, at leastfor part of its length.
 7. An assembly as claimed in claim 6 whereinsaid downstream portion further comprises a cylindrical portionconnecting said frusto-conical portion to said valve seat.
 8. Anassembly as claimed in claim 1 in which said longitudinal axis of saidvalve is inclined in relation to said axis of said cylinder and saidfirst axis is situated in the acute angle formed between saidlongitudinal axis of said valve and an imaginary line extending at rightangles to said axis of said cylinder.
 9. An assembly as claimed in claim1 wherein said downstream portion of said passage comprises afrusto-conical portion and a cylindrical portion, said frusto-conicalportion of said downstream portion being connected to said intermediateportion of said passage and said cylindrical portion connecting saidfrusto-conical portion to said valve seat, said intermediate portion andsaid cylindrical portion and said frusto-conical portion of saiddownstream portion intersecting said plane containing said axis of saidcylinder and said longitudinal axis of said valve at a point lying onsaid plane.
 10. An assembly as claimed in claim 1 in which said passagefurther comprises a partially spherical portion disposed between andconnecting said upstream and intermediate portions, said upstream andintermediate portions being tangential to said partially sphericalportion.